CVE-2026-72018: dibs: loopback: validate offset and size in move_data()

From: Greg Kroah-Hartman <[email protected]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

dibs: loopback: validate offset and size in move_data()

The loopback move_data() performs a memcpy into the registered DMB
without checking whether offset + size exceeds the DMB length.  Unlike
real ISM hardware, which enforces memory region bounds natively, the
software loopback has no such protection.

A peer-supplied out-of-bounds offset or oversized write would result in
an OOB write past the allocated kernel buffer.  Add an explicit bounds
check before the memcpy to reject such requests with -EINVAL.

The Linux kernel CVE team has assigned CVE-2026-72018 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.10 with commit f7a22071dbf316c982fb44308874bd7ad9ac2091 and fixed in 6.12.97 with commit ee188a6b264b71315a67f1b9470faad308b730d2
	Issue introduced in 6.10 with commit f7a22071dbf316c982fb44308874bd7ad9ac2091 and fixed in 6.18.40 with commit b2f426a9a22886071966432ede8fceafffe12b8c
	Issue introduced in 6.10 with commit f7a22071dbf316c982fb44308874bd7ad9ac2091 and fixed in 7.1.5 with commit 94fe0ab01b480b52bd8f977edbd845ef375d69fd
	Issue introduced in 6.10 with commit f7a22071dbf316c982fb44308874bd7ad9ac2091 and fixed in 7.2-rc3 with commit 78237e3c0720fcc6eb9b87e90fd70f63eeca886f

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-72018
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/dibs/dibs_loopback.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/ee188a6b264b71315a67f1b9470faad308b730d2
	https://git.kernel.org/stable/c/b2f426a9a22886071966432ede8fceafffe12b8c
	https://git.kernel.org/stable/c/94fe0ab01b480b52bd8f977edbd845ef375d69fd
	https://git.kernel.org/stable/c/78237e3c0720fcc6eb9b87e90fd70f63eeca886f